This invention relates to an electronic musical instrument, and more particularly to a keyboard type electronic musical instrument including a voltage controlled tone signal generator.
With a prior art electronic musical instrument, the tone signals derived upon key operation from tone generators are filtered by a tone coloring filter (lowpass filter) having a preselected frequency characteristic to impart a desired tone color to the tone signal. Namely, the cutoff frequency of the tone coloring filter for determining its passband is predetermined to a specified value. Particularly in the pedal tone pitch range, therefore, the balance in respect of tone color and tone volume between a higher pedal tone and a lower pedal tone is lost due to the loudness characteristics of the human ear to generate unnatural musical sounds. This is because, in case of comparison of a lower tone with a higher tone in the pedal tone pitch range, the human ear has a lower sensitivity to the lower tone.
Also with a recently developed synthesizer type electronic musical instrument having a voltage controlled oscillator and a voltage controlled lowpass filter and designed to control the cutoff frequency of the lowpass filter in accordance with the control voltage waveforms whose voltage levels vary as a function of time, arrangement is not so made that the control voltage waveform applied, in case of a higher pedal tone, to the lowpass filter is different from that in case of a lower pedal tone. As a result, there is produced an undesired difference in respect of tone color and tone volume between the lower pedal tone and the higher pedal tone, as in the case of the abovementioned prior art electronic musical instrument.